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![Photoelectric ray to determine flying ceiling. Washington, D.C., June 15. To permit a ground observer to determine at what height flying is safe during days of fog and heavy overcast, Miss Elizabeth M. Zandonini, of the Radio Section staff of the Bureau of Standards, is shown with the balloon transmitting equipment. A photoelectric cell measuring light brightness is used to control the pitch of the radio signal transmitted from the balloon as it ascends. A graphical frequency recorder plots the pitch and hence [...] a measure of the light brightness as a function [...] height. The experiments are carried on for the U.S. [...]](https://cache.getarchive.net/Prod/thumb/cdn4/L3Bob3RvLzE5MzcvMDEvMDEvcGhvdG9lbGVjdHJpYy1yYXktdG8tZGV0ZXJtaW5lLWZseWluZy1jZWlsaW5nLXdhc2hpbmd0b24tZGMtanVuZS0xNS10by1wZXJtaXQtNjQwLmpwZw%3D%3D/40/49/webp "Photoelectric ray to determine flying ceiling. Washington, D.C., June 15. To permit a ground observer to determine at what height flying is safe during days of fog and heavy overcast, Miss Elizabeth M. Zandonini, of the Radio Section staff of the Bureau of Standards, is shown with the balloon transmitting equipment. A photoelectric cell measuring light brightness is used to control the pitch of the radio signal transmitted from the balloon as it ascends. A graphical frequency recorder plots the pitch and hence [...] a measure of the light brightness as a function [...] height. The experiments are carried on for the U.S. [...]")
Related
Vrouw aan het werk in haar keukentje, Bestanddeelnr 252-9342
Summary
Nederlands: Collectie / Archief : Fotocollectie Van de Poll
Reportage / Serie : Bewoners van een appartementengebouw in Parijs
Beschrijving : Vrouw aan het werk in haar keukentje
Datum : 1950
Locatie : Frankrijk, Parijs
Trefwoorden : interieurs, keukens, vrouwen
Fotograaf : Poll, Willem van de
Auteursrechthebbende : Nationaal Archief
Materiaalsoort : Negatief (zwart/wit)
Nummer archiefinventaris : bekijk toegang 2.24.14.02
Bestanddeelnummer : 252-9342
Tags
Date
1950
Source
Nationaal Archief
Copyright info
Public Domain Dedication (CC0)
